This invention relates to pressure sensitive adhesive label construction, particularly to thin label constructions having radiation cured face films.
Conventional pressure sensitive adhesive labels are adhered to the release surface of a carrier web in spaced apart relation. The web may be a plastic film but is usually a smooth paper, such as glassine, or kraft coated with a silicone release layer. The labels include a layer of pressure sensitive adhesive in contact with the release layer on a carrier web and a label facestock which may include indicia in one or more colors printed over the label facestock. The facestock may be paper or plastic such as vinyl. Indicia take the form of printed words, letters, or designs. Because such indicia are printed over the label facestock, they are subject to wear and abrasion. Clear protective coatings are sometimes applied over the indicia. Such labels, with or without printed indicia, are referred to as "laid-on" labels and they are in wide commercial use for attachment of various articles and materials for identification, advertising, decoration, or protection.
Laid-on labels are made by die cutting as described in U.S. Pat. Nos. 2,391,539 and 3,166,186, for example. A sheet or roll of a laminated construction comprising a layer of label facestock, a layer of pressure sensitive adhesive, and a temporary carrier web having a release surface in contact with the adhesive is provided. Discrete labels are formed on the carrier web by die cutting through the label facestock and the adhesive layer, without cutting through the carrier web, to define the periphery of individual labels. The facestock and adhesive surrounding the individual labels remain as a continuous, skeletal web or matrix which is then stripped from the carrier web leaving discrete spaced apart labels adhered to the carrier web. Indicia may be printed on the labels before or after die cutting and stripping of the matrix. Protective coatings may also be applied before or after stripping of the matrix. The practice of making laid-on labels by die cutting and stripping of matrix is wasteful of materials and entails the use and maintenance of precision die cutting machinery.
Laid-on labels having an adhesive layer in contact with the release surface of a carrier web are typically dispensed in one of two ways. An individual label may be manually peeled from the carrier sheet and applied to a substrate. Alternatively, the carrier web may be bent over a sharp angle, for example, by drawing the carrier across an edge. The label is less flexible than the carrier web and fails to follow the carrier around the sharp angle, but instead becomes at least partly separated from the carrier web. The separated portion of the label may be applied directly to a substrate or grasped manually for removal from the carrier web. In both of these methods of label dispensing it is necessary that the label itself have sufficient rigidity and strength to survive removal from the carrier film and transfer to a substrate. In addition when a label is manually removed from carrier web it must have sufficient thickness to be readily grasped by the user.